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HT patients with concomitant diseases can be treated by: –Patients with renal failure: the safest drug is hydralazine (it  renal blood flow). If not active give Lasix + Aldomet. Alternatively a non-polar  -blocker (Inderal) or Clonidine can be used. Inderal is excreted via the liver (& is contraindicated in hepatic failure). –Patients with hepatic failure: can be treated with a polar  -blocker (e.g. pindolol, nadolol or atenolol). These are excreted mainly via the kidney. –Patients with bronchial asthma: can be treated with a selective  -blocker (e.g. metoprolol or atenolol). Better agents might be ACEI / CCBs / AIIRAs. –Patients with CHF: can be treated with captopril & / or prazocin. –Patients with tachycardia: can be treated with a non-selective  -blocker (e.g. nadolol or propranolol). (BB without ISA) –Patients with depression: hydralazine is the drug of choice (reserpine, guanithidine, methyl dopa & clonidine can cause depression). Hypertensive crisis is treated by sodium nitroprusside & diazoxide (given by IV infusion or injection) as they have a direct vasodilating effect on blood vessels. Diazoxide: is a direct vasodilator. If administered orally, it has a mild antihypertensive effect. It is usually given by rapid IV infusion to  BP rapidly in patients with hypertensive crisis. Metyrosine (Demiser): is an antihypertensive used in pheochromocytoma. Papaverine: is used primarily for its ability to produce vasodilatation. It causes relaxation of arteriolar smooth muscles. A sudden increase in blood pressure will cause reflex bradycardia. Postural hypotension: response to drug is greater in the erect than in the supine position. This is a characteristic effect of the drugs that block the sympathetic NS. Orthostatic hypotension, either due to direct action on arterioles or via CNS, is caused by: –Vasodilators – Guanithidine –  1 - blockers. – MAO-Is (antidepressants) Acetylcholine: has a direct effect on the heart  coronary vasodilatation. Both nitroglycerine & isosorbide dinitrate (Isordil) are available in sublingual dosage forms used as coronary vasodilators in the treatment &/or prophylaxis of anginal attacks. Both agents are equally active. Hydergine is claimed to be a mood elevator is also available as sublingual tablets. Dopamine (Inotropine) in cardiogenic shock: is an inotropic sympathomimetic. it  contractility with less effect on HR at low doses. It  vasodilatation & renal perfusion through its action on  1 receptors. Its major advantage is that it produces dose dependant  in CO & renal perfusion. Compared to nitroglycerine tablets, nitroglycerine ointment provides a prolonged effect.

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Quinidine: –It is used for supraventricular arrhythmias. –It is the drug of choice in atrial premature contractions. –It is used in ventricular premature contractions (VPC). –It is given orally or IV. –Quinidine should not be used without prior degitalization, because it may increase the frequency of impulse transmission. Procainamide (Pronestyl): –It is used in VPC & ventricular tachycardia. –It is contraindicated in CHF as it causes Lupus like reactions (SLE). Disopyramide (Rhythmadon): –Used in the treatment of VPC & repetitions. –Used in ventricular arrhythmias. Lidocaine (Xylocaine): –It is used in the treatment of ventricular arrhythmias (  HR). –It is the drug of choice in arrhythmias associated with emergencies (MI, open heart surgery, digitalis intoxication…) –The anti-arrhythmic effect of lidocaine is:  No effect on SA node (unlike quinidine).  Suppress automacity in Purkinje fibers & atrium.  Depression of phase 0 depolarization (  Na influx) (it is depressant but not like procainamide/quinidine).  It  the effective refractory period on Purkinje fibers & inhibit the duration of action potential.  Show very little changes of ECG. Phenytoin (Dilantin): –It alters Na + conc. by promoting Na + influx. –It is used in the both ventricular & supraventricular arrhythmias. –It is also used in digitalis induced arrhythmias. Propranolol (Inderal): is most valuable in atrial arrhythmias (tachycardia). N.B: Proximal sinus arrhythmia: may result from an increase in temp. N.B: Catecholamines may cause arrhythmias.

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Oral Hypoglycemic Drugs Oral Hypoglycemic Drugs: They are classified in 2 groups: –Sulfonylurea derivatives. –Biguanides. Sulfonylurea derivatives: are used to treat type II diabetes. –Mechanism of action:  These stimulate the  -cells of the pancreas to secrete insulin.  They also decrease glycogenolysis.  May cause hypoglycemia. –Acetohexamide (Demilor): is reported to have a uricosuric effect  It is metabolized to a compound having equal or greater hypoglycemic activity. –Chlopropamide: has an antidiuretic effect which may be useful in diabetes insipidus.  It has the longest duration of action (t ½) of all oral hypoglycemics (require several weeks to be completely eliminated from the body after discontinuation). –Tolbutamide (Rastinon): is totally metabolized to the inactive form. –Tolazamide (Tolinase): is more slowly absorbed from the GIT than other compounds. –Glipizide (Amaryl): Excreted via the liver. Biguanide derivatives: –Mechanism: potentiate action of insulin on glucose (activate pancreatic insulin). –Metformin (Glucophage): Excreted via the kidney  Indicated in obese diabetics, where hyperglycemia is due to ineffective insulin.  Side effects: weight loss, lactic acidosis, metallic taste, GIT upset. –Phenformin Diabetes insipidus: –Is a central endocrine disorder characterized by  secretion of ADH from the pituitary (hypothalamus)  excessive urinary output (urine output  from 1.5 l  18 L)  thirst –Treated with lypressin (vasopressin analogue) –Increased urinary output in DM: is due to the osmotic pressure of glucose in urine Oral anti-diabetics: Sulphonyl ureas: activate receptors on B-islets cells of pancreas  Release more insulin in response to glucose; they do not ↑ insulin formation and they may cause hypoglycemia, and weight gain; e.g. Tolbutamide & Glipizide Biguanides: reduce production of glucose in liver. Used for obese patients; e.g. Metformin Glucosidase Inhibitor:↓ breakdown and absorption of carbohydrates; e.g. Acarbose

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Oral anti-diabetics: Sulphonyl ureas: activate receptors on B-islets cells of pancrease  Release more insulin in response to glucose; they do not ↑ insulin formation and they may cause hypoglycemia, and weight gain; e.g. Tolbutamide & Glipizide Biguanides: reduce production of glucose in liver. Used for obese patients; e.g. Metformin  -Glucosidase Inhibitor: ↓ breakdown and absorption of carbohydrates; e.g. Acarbose

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Classification of Insulin: insulin can be classified according to onset & duration of action. ClassOnsetDurationExamples –Fast acting0.5-1 hr6-8 hrsCrystalline or Soluble insulin Acid regular insulin Neutral regular insulin Semi-lent (susp. small particles) –Intermediate2 hrs24 hrsIsophane insulin suspension Insulin Zn suspension Globin Zn insulin NPH & Lent (lent = 30% semilent + 70% ultralent) –Long acting4 hrs36 hrsProtamine Zn Insulin 6-8 hrsUltralent (extended Insulin Zn) (a suspension of large particles) Mechanism of action of insulin: –Enhances glucose utilization in peripheral tissues. –Increases glucose storage in form of glycogen in liver & skeletal muscles, through enhancing the hexokinase enzyme  glucose-6-phosphate formation. –It is anabolic, enhancing protein synthesis. –Decreases fat catabolism & enhances lipogenesis. –It decreases gluconeogenesis (i.e.  conversion of amino-acids  glucose) Insulin degradation: occurs in the liver as well as the kidneys. Insulin when injected IV has a short plasma t ½ of 9 min. Crystalline Zn insulin: is the only insulin (regular intermediate acting) that can be used IV in case of diabetes ketoacidosis Insulin has a large volume of distribution which approximates that of extracellular fluids. When low conc. of insulin (20 units) is indicated in LVPs, only soluble insulin (not suspension) can be used. Additionally, the % of insulin adsorbed on the walls of the container or administration set is significant (not less than 50% loss). Single peak insulin: means that it displays a single protein peak when assayed chromatographically. (Not all antigenic components are removed ~99%). It has higher degree of purity compared to older insulin preparations. Most insulin preparations used in USA are single peak, i.e. single component. Single component insulin: means from 1 source only (pork or beef). Diabetic patients sensitive to foreign proteins: appear to tolerate pork insulin rather than beef insulin. Tletin II is a single component, pork insulin, for highly sensitive diabetics.

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